Simulation, as kqr said. I like to use the classic queue theory results (e.g. results on M/M/1 and M/M/c) as unit tests for the simulators I build. I've found t

Simulation, as kqr said. I like to use the classic queue theory results (e.g. results on M/M/1 and M/M/c) as unit tests for the simulators I build. I've found that application of queue theory very helpful in avoiding silly simulation bugs.